The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials, design, and fabrication tools have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of these advances, fabrication methods, tools, and materials have struggled to realize the desire for smaller feature sizes.
Lithography is a mechanism by which a pattern is projected onto a substrate, such as a semiconductor wafer, having a photosensitive layer formed thereon. The pattern is typically induced by passing radiation through a patterned photomask. Lithography tools and methods have experienced significant advances in decreasing the line width of an imaged element. This decreased line width also increases the challenges in providing a quality coating onto a patterned surface. Although existing methods including deposition of layers for photolithography and other processes have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.